Interpreting Motion

1. Interpreting Motion How to read a position vs. time graph.

2. Position vs. Time Graphs Stationary Constant positive velocity Constant negative velocity

3. Position vs.Time graphs Changing velocity (increasing) Changing velocity (decreasing)

4. If you want to know what the average velocity is calculate the slope. Slope = Δd / Δt =Vavg Δd = df - di Δt = tf - ti

5. Using slope to predict motion • On a position vs. time graph • If slope is 0, then velocity is 0. • If slope is positive, velocity is constant in positive direction. • If slope is negative, velocity is constant in the opposite direction. • If slope is changing, velocity is changing. (i.e. you are accelerating)

6. d(m) A Object A is stationary at some positive position from the origin. t(s)

7. d(m) B Object B moves away from origin with a constant positive velocity. t(s)

8. d(m) C Object C starts at a positive position and moves away from the origin with a constant positive velocity. t(s)

9. d(m) Object D moves away from the origin at a constant positive velocity. D t(s)

10. d(m) C Same velocity as B. B A D Slower than B or C. t(s)

11. E A East B High St. D C West

12. On your own… pg 85 #2-3 and pg87 #5 and 8

13. Finding the Equation m = ∆y/∆x (6m- 4m)/ (2s-1s)= 2m/s d = 2t+2 y = y = mx +b x =

14. Finding position Vavg = Δd / Δt Vavg = (df –di)/Δt df = di + Vavg Δt y = b + mx

15. On your own… pg 89 #9-12